The interval between infection and appearance of a disease is known as:

Options

A. Inoculation period
B. Incubation period
C. Infection period
D. Penetration period.

Answer

To answer the question "The interval between infection and appearance of a disease is known as:", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify the term that describes the time period between when an infection occurs and when the symptoms of the disease start to appear.

2. **Review the Options**: The options provided are:
- Inoculation period
- Incubation period
- Infection period
- Penetration period

3. **Analyze Each Option**:
- **Inoculation Period**: This term is related to the process of vaccination and not relevant to the interval between infection and disease symptoms. Therefore, it is incorrect.
- **Incubation Period**: This term refers specifically to the time between exposure to an infection and the onset of clinical symptoms. This is the correct answer.
- **Infection Period**: This term usually refers to the time when symptoms are present, which is after the incubation period. Thus, it is incorrect.
- **Penetration Period**: This term does not relate to the context of disease and infection; it refers to the act of inserting one object into another. Therefore, it is also incorrect.

4. **Select the Correct Answer**: Based on the analysis, the correct term for the interval between infection and the appearance of a disease is the **Incubation Period**.

### Final Answer:
The interval between infection and appearance of a disease is known as the **Incubation Period**.

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